1. Field of the Invention
The present invention relates generally to power consumption in a User Equipment (UE) in a mobile communication network, and more particularly, to reduction of power consumption in a UE of 2G, 2.5G or 3G mobile communication network when the UE is in an idle mode.
2. Description of the Related Art
As per Global System for Mobile communication (GSM) specifications, once a UE is in an idle mode and the UE has received a neighbor cell list, the UE performs neighbor cell measurements at a periodic rate irrespective of prevalent network conditions. This activity leads to higher power consumption in the UE.
Attempts at resolving this unnecessary power consumption issue have been addressed in 3G system (UMTS), where the UE performs measurements only when the UE is in a poor signal area (defined by the usage of S_intrasrch, S_intersrch and S_srchRAT). Further efforts to address this power consumption issue are found in U.S. Pat. No. 6,331,971, where the UE or other remote units are able to sleep for a longer period of time, thus extending the battery life of the UE, by optimizing the periodicity at which the UE measures control channels on a neighbor cell list to determine whether a new control channel should replace the serving control channel. This requires modification of a paging frame class, which has been assigned to a UE. The UE can then monitor the paging channel at intervals making it more battery conservative for the UE because it is based on current communication conditions.
U.S. Pat. No. 6,067,460 proposes a method of optimizing power consumption by avoiding measurement of the neighbor cells when a UE is stationary or moving slightly with respect to the serving cell and with respect to the neighbor cells, until it determines that it is no longer stationary. The stationary condition of the UE is deduced using measured Received Signal Strength Indication (RSSI) values of the serving cell and neighbor cells.
Thus, efforts have been made to optimize the power consumption in the UE of a 3G system when the UE is in the idle mode, however a need still remains for the reduction of power consumption in the UE when the UE is in the idle mode. The stationary/non-stationary condition of the UE, which is determined using a change in absolute value/rate of change of signal strength of a serving cell and neighbor cells is insufficient for determining suitability for avoiding neighbor cell measurements.